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What is i spec a/b
NB: Originally posted elsewhere on the Global Riders Network and appears via syndication.
Hello everyone!
Question i've had for years now. What is the difference between I Spec A and B?
Ive got the saint brakes and i want to get xtr shifter to replace my sram x7. So i'm just curious which configuration i need. Im running 1x10 so i only need the 10speed right hand. Im pretty sure i can run them both on the same clamp with one of the configurations but not sure which one.
Thanks,
Jono.
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A and B aren't compatible. I bought a set of B adapters but found I had A shifters. Ended up buying a set of B I-spec shifters. XT were cheap enough and XTR was a whole lot more money for just a few grams savings.
If your bike is the current model year it will be I-spec B.
my bike is current model but the brakes are additional. Shimano website says they are i spec compatible????
Normally i would just go xt but i found an awesome deal on the shifter that i would be silly to turn down. Ill probably just go xt for the shifter. Im really not a fan of sram stuff.
Silly question but you know the xtr shifter won't be compatable with the x7 deraileur, yeah?
So if you are changing you need both shifter and rear mech
funnily enough i actually didn't no that, but i do plan on changing the rd as well so thats not an issue.
I found this site a while ago, has a nice picture of the differences between the brakes, scroll down a bit...
http://www.trickstuff.de/en/products/clapton_KL.php
do similar stuff to trickstuff and might be easier to get a hold of if you end up needing them. I have problem solvers and they work but to be honest the trickstuff looks far more refined.
Sorry Jonathon, I can't find anything that actually explains exactly what the difference is.
On the link provided, if you look at the post titled "Identifying your I-Spec Version", there's a picture they've taken where they show difference between each type of I-Spec brake lever.
The post almost directly below that then has a diagram from Shimano which shows how the shifters integrate with the brake levers.
It's to do with the way the shifters and brake levers join together. In I-Spec A, the shifter pretty much bolts directly the lever. In I-Spec B, the shifer attaches using a floating barrel style bolt arrangement.
From memory, I-Spec B Shifters will attach to either A or B brake levers, but I-Spec A shifters will only attach to I-Spec A brakes.
So, look at your brake levers to determine whether they have the hole or not, and this will tell you what you have.
This is way more complicated then it needs to be! Thanks for the help.
So im pretty sure ive identified my brakes as i spec A and the shifters i want are i spec B. Which i think will work, just as long as its not the other way around?
I even went to the lbs and they had no idea what i was on about.. They couldn't give me an answer - unless they didn't want to?
Not surprised the LBS had no idea. There's a lot of stuff to keep on top of, and as most LBS's have vacated the parts space to on-line retailers they just don't have the familiarity any more.
Some like Ride-In Workshop might be an exception as building and servicing bikes is their bread and butter.
Yep, you'll be good with I-Spec A Brakes a B shifters. You'll need the particular attachment, method, but it can work.
Problems when I decided to take off my avid brakes and instal XT's. I thought the Brakes that I bought were the i-Spec A, but when they arrived were i-Spec B, my X7 shifters would not bolt up, I bought a set of Problem Solvers and did run them for a little while, but in my opinion I thought the shifters were a little far away from my bars, as the adapters lower them away from the Brake Lever. I have since just bought Sram X7 Handlebar Clamps and I know it adds a little extra stuff on the Bars, but as said it feels more comfortable this way but that's my personal opinion.
I-Spec compatibility is a complete mess - I don't know what Shimano were thinking!
Here's the official compatibility diagram from Shimano. In it "Conventional" is I-Spec A and "New" is I-Spec B...
What it means is that an I-Spec B shifter will fit on either I-Spec A or B lever, but needs different hardware (both sets of mounting hardware come with a proper boxed set of shifters, but OEM's only usually come with the hardware for mounting to B type levers).
I-Spec A shifters will only fit on I-Spec A levers.
You can tell if you've got I-Spec A or B levers/shifters because I-Spec B will have a "B" in the model number - for example BL-M785-B are XT I-Spec B levers. The I-Spec A equivalent doesn't have an "A" in the model number, it's just BL-M785. Or just identify what you have from the diagram above.
And if things weren't already complicated enough, the new 11 speed XTR 9000 series is a third I-Spec standard called I-Spec II which isn't compatible with either A or B!!
Does anyone no if the shifters will come with both sets of mounting bolts? I have a feeling i will have issues trying to mount them up to my i spec a brakes when i get them.
A proper retail boxed set of B shifters will come with mounting hardware for both A and B levers.
However, some of the online retailers (including the big ones, I'm not just talking about E-bay) sell "OEM" shifters packaged in just a plastic bag which were destined for a new bike build. These often only come with the hardware for mounting to B levers.
For example, I bought a set of XTR shifters from Merlin and they only came with the bolts for B levers and no cable outers, so I sent them back and got the same shifters from Wiggle (and got them to price match Merlin) and they were a proper boxed set with both sets of bolts and cable outers. You'll have to ask whoever you're buying from to be sure. However, if you still get caught out you can buy the mounting hardware separately - Shimano part number Y-6UV98090.
So i asked and they told me its a retail set that comes with all the bolts and stuff so i put my order in. xt shadow + medium cage and xtr shifter
:D 
WE shall see how i go... running 11-36 cassette. And a 30t chanring.
If i add teeth to the chainring will that give me better acceleration or is that if i take away teeth teeth from the chainring?
Thanks for the help everyone.
legs spin at the same cadence then adding teeth to your chain ring will increase speed, not necessarily acceleration.
I assume you ordered the XTR M980 shifter, not the XTR M9000?
SL-M980-B shifter is 10sp and I-Spec B so compatible with XT RD and Saint levers.
SL-M9000-I shifter is 11sp and I-Spec II and not compatible with XT RD or Saint levers.
Yep the M980 I-Spec B - gotta love runnnout deals!!!